Prying Open the Mind's Eye: Meditation Reduces the Attentional Blink

Attention training through meditation can reduce the duration of the "attentional blink" - in which detection of a first rare target causes people to be unaware of a second target presented soon after the first - according to research by Slagter et al from PLoSBiology.

The attention blink effect is "attentional" because it only occurs when subjects actually detect the first target, and therefore reflects some kind of a refractory period for attentional orienting: consider it the duration of the "blink" of the mind's eye. You can try it here.

Slagter et al administered pre- and post-training tests of the attentional blink to a control group of subjects interested in meditation, as well as an experimental group who underwent a 3 month Vapissana meditation retreat. For our purposes here, Vapissa meditation might be considered a type of mindfulness meditation, because it cultivates a "concentrative" focus on breathing, as discussed last week.

Only the experimental group showed post-test increases in their ability to detect the second target, indicating a shortened attentional blink. This did not reflect a general increase in vigilance, as the meditation-related improvement did not occur outside of the time window in which the blink is normally observed (obviously, given a certain interval between the first and second targets, no one will show an attentional blink). Nor did this reflect a pre-test difference between groups in the attentional blink, as confirmed through covariance analyses.

The authors also analyzed scalp electrical potentials evoked by the first of the two sequentially presented targets, with the prediction that the meditation group would allocate attention differently to that first target (as indexed by the p3b response, known to relate to attentional orienting). The meditation group actually showed a lower p3b response to the first target, relative to the control group - indicating that attention was more effectively allocated to the first target. In addition, the extent to which subjects showed this lowering of the p3b predicted their ability to detect the second target.

Thus Vapissana meditation seems to have streamlined one rate-limiting factor of human performance: temporal limitations in attention and orienting to important features in the environment.

However, these results differ significantly from those discussed earlier in the context of meditation. For example, Jha et al's work reports an effect of previous meditation experience; based on that work, we'd expect that the effects of meditation training would be stronger (or at least different) based on the number of hours of previous meditation experience. Second, it seems that detection of the second target would rely on the ventral attentional system, involved in generating the p3 response known to occur in the attentional blink paradigm. It is possible that the Slagter et al results reflect improvement in the ventral system, despite reports that improvements in that system take longer to manifest - perhaps not as long as the 3-month retreat used here.

Also, perhaps as implied by the BPS Research Digest post on this study, meditation might have had its effects by "de-automatizing" or "untraining" the tendency for subjects to allocate so many attentional resources to a rare but briefly presented target. This kind of mechanism would bring these results in line with those reported in the Stroop paradigm, in which the interference from automatic word reading processes can be reduced or eliminated after meditation training.